Many types of electrochemical cells utilize a liquid ionically conductive medium to support electrochemical reactions within the cell. For example, a metal-air electrochemical cell system may comprise a plurality of cells, each having a fuel electrode serving as an anode at which metal fuel is oxidized, and an air breathing oxidant electrode at which oxygen from ambient air is reduced. Such a cell may include the liquid ionically conductive medium to communicate the oxidized/reduced ions between the electrodes.
In some electrochemical cell systems utilizing a liquid ionically conductive medium, an air-permeable but liquid-impermeable membrane is utilized as part of the oxidant electrode, so as to permit the oxygen from the ambient air to enter the oxidant electrode, while preventing the liquid ionically conductive medium from escaping (i.e. leaking out of) the electrochemical cell. The air-permeable but liquid-impermeable membrane may be coupled to an active layer of the oxidant electrode, such that active materials in the active layer contact the liquid ionically conductive medium to facilitate electrochemical reactions within the cell. In some cases, the air-permeable but liquid-impermeable membrane may be laminated to the active layer and/or a current collector screen for the oxidant electrode. In some cases, the layers, screens, and membranes of the oxidant electrode may be bonded together, potentially utilizing a variety of pressing or rolling techniques, and may form a solid unit suitable for assembly into the housing of the electrochemical cell.
In some cases, one or more glues may be utilized to bind the oxidant electrode to the housing. It may be appreciated, however, that in some cases the glue might suffer adhesion issues with the current collectors. Such issues may particularly be an issue at the borders due to assembly processing of the oxidant electrode. For example, in some cases assembly of conventional oxidant electrodes may potentially result in the current collector protruding through a face of the oxidant electrode in some areas. Additionally, such issues may result in seepage of ionically conductive medium through or around the edges of the oxidant electrode. Among other improvements, the present application endeavors to provide an effective and improved oxidant electrode composition that may prevent issues of glue adhesion or other leakage of the ionically conductive medium at the borders of the oxidant electrode, without adversely affecting the performance of the cell during operation.